<http://schema.org/description>
"In the 1980s, people living on houseboats in the San Francisco Bay were puzzled by a droning hum of unknown origin that started abruptly in the late evening and stopped suddenly in the morning."^^<http://www.w3.org/2001/XMLSchema#string>
<http://exceptionmag.com/23464/melatonin-tells-these-fish-to-hum-all-night/>